Lubricating and cooling system for bearings and pistons



Marshl 12, 1940- H. H. BLACHE ET AL LUBRICATING AND COOLING SYSTEM FOR BEARINGS AND PISTONS Filed Aug. 9, 1938 3 Sheets-Sheet l E y i 7%2 March 12, l1940.

H'. H. BLACHE ET AL LUBRICATING AND COOLING SYSTEM FOR EARINGS AND PISTONS Filed Aug. 9, 1938 5 Sheets-Sheet 2 March 12, 1940. H. H. BLACHE ET AL LUBRICATING AND COOLING SYSTEM FOR BEARINGS AND PISTONS Filed Aug. 9, 1938 3 Sheets-Sheet 5 Patented Mar. 12, 1940 LUBRIOATING AND COOLING, SYSTEM FOR n BEARINGS AND PIST'ONS I Hans Henrik Blache and Frederick' Ernest Rebbeck, Belfast, Ireland Application August 9,

193s, serial No. 223,954

In Great Britain August 14, 1937 5 Claims.

This invention relates to single-acting internal combustion engines having oil-cooled pistons articulated by means of cylindrical gudgeon-pins to the connecting rods, and the invention has for its object to` provide improved means for lubricatingl the gudgeon-pin bearings and for cooling the gudgeon-pin and piston.

It is known to divide the oil supply from an oil pump into a dual-flow stream, one stream cooling the pistons and the other stream lubricating the gudgeon-pin bearings. known to supply lubricating oil through the connecting rod to the gudgeon-pin bearings and to return the oil therefrom into thecrank-case chamber through another passage in the connecting rod, while oil for cooling the piston is supplied through the connecting rod and gudgeon-pin to a cooling space in the piston, from whence it is discharged into the crankcase chamber through telescopic pipes or other means arranged to establish a liquid passage between the moving piston and the crankcase chamber independently of the connecting rod.

The present invention has for its ob- 25 ject to avoid dual -flow or dividedl flow systems without the use of telescopic pipes or any other means of establishing an oil passage from the piston to the crankcase chainber independently of the connecting rod. Thus is attained an engine simpler in design and cheaper to build, in which also all moving parts in the crankcase chamber are more easily overhauled and maintained.

According to the present invention, in an internal combustion engine having an oil-cooled single-acting piston articulated by'mea'ns of a cylindrical gudgeon-pin to a connecting rod, the whole of the stream of oil used for cooling the piston also passes through thegudgeompin and through lubrication grooves between the gudgeen-pinv and its bearing bush in the passage of the oil as a continuous and single uniflow current vwhich is supplied to a supply passage in the connecting rod and returns toa return passage in the connecting rod. Consequently, the whole of the'stream of oil used for coolingthe pistonis not only used to cool the gudgeon-pin, but is also utilised to build up a continuously flowing lmof oil lbetween the gudgeon-pin and its bearing bush and this continuously owing film of oil serves both to lubricate and to carry away heat from the bearing faces of the gudgeon-pin and its bearing bush.

`The whole of the oil passes in sequence 'rst through the gudgeon-pin, then through a cooling It is also (Cl. 12S-176) chamber in the piston and nally through lubricating grooves between the gudgeon-pin and its bearing bush, in the ow of the oil from and to the connecting rod, but this sequence may be varied so long as the whole of the oil stream used for cooling the piston also passes through the hollow gudgeon and 'through the lubricating grooves between the gudgeon-pin and its kbearing bush. Asboth the supply and return of the whole'l I' quantity of oil required for coolingl the piston and for cooling and lubricatingthe gudgeon-pin and its bearing bush takes place `through connecting rod, we avoid the use of any oil piping connecting the moving piston to the crankcase vchamber independently of the connecting rod, and we avoid dividing the oil stream into one stream for cooling the piston and another' stream or streams for lubricating the gudgeon-pin bearing faces. y The invention is applicable more particularly, but is not restricted wholly, toengines in which the hollow gudgeon-pin is Xed in lbosses on thev piston or a crosshead and is fittedin a bearing Abush whichv is'xed in the eye of the connecting rod. I The accompanying drawings illustrate the preferred manner of carrying out the invention. On

the drawings, Fig. 1 shows a longitudinal verticaliv section through a trunk piston and the upper end of the connecting rod articulated thereto. Fig. 2 is a vertical sectional view at right angles to the sectional plane of Fig. 1 showing the conf necting rod with its bottom or big-end bearing and top or Small-end bearing, the piston beingv omitted. Fig.y 3 is a horizontal sectional View looking on the lower partof the top-end bush. Fig. 4 isa side view oi the piston andupper end of the connectingr rodwith the piston partly broken away to show* the connecting rod-top end. y I Figs. Sand 6 are Views at right angles to one another showing the invention applied to a sliding crosshead connecting apiston rod to a connecting rod. Fig. 5 shows the piston rod' end in vertical section and Fig; 6 shows the parts in side view.r

Referring firstly to Figs. l to 4, 1 designates a trunk piston provided in its upper part with a cooling space and provided below the same with stepped'gudgeon-pin bosses, the upper steps 9a ybeing nearertogether than the lower steps 9b, as clearly seen in-Fig. 4, to accommodate the correspondingly stepped top end Illa, lilb ofthe' connecting rod l0. The stepped top end ofA ther connecting rod l 0 is drilled to receive a similarly stepped bush or sleeve Il. The bush II and is fixed within the hole in the connecting rod top end and acts as a bearing sleeve for the top end of the connecting rod on the gudgeon-pin I2 during the angular movement of the connecting rod. The gudgeon-pin I2 is prevented from turning in the piston either by a key I3 or a step screw I4 or by both means or their equivalent. Fig. 4 shows the gap I5 which allows for the angular movement of the connecting rod.

The wall of the cooling space 8 in the piston is provided with an inlet passage I6 and an outlet passage iT for the piston cooling oil, these passages registering with holes I8 and I9 respectively in the tubular gudgeon-pin I2. Driven into the bore of the gudgeon-pin I2 is a distribution member 20 having both ends shaped as solid discs making an oil-tight t in both ends of the hollow gudgeon-pin i2. The distribution member 2i) has a part 23a of substantially smaller diameter than the bore of the gudgeon-pin; this part 20a has a hollow interior 2|, which communicates by way of an inlet passage 22 with a radial hole 23 inthe gudgeon-pin above the connecting rod. The space 2| also communicates through a passage 251 and through the hole I8 in the gudgeon-pin I2 with the passage I6 leading into the piston cooling space 8. The outlet passage Il from the cooling space 8 communicates through the hole I9 in the gudgeon-pin with the space 25 between the Uudgeon-pin and the reduced part 23a of the distributing member 20. A number of radial holes 23 in the lower part of the gudgeonpin connect the space 25 with relatively deep oil grooves 2 in the bush vi I. These oil grooves 21 have a capacity sufficient to pass not only the amount of oil necessary to lubricate and cool the gudgeon-pin, but in addition to pass the Whole quantity of cooling oil from the piston space 8. To enable the oil grooves 2'I to be made suiciently deep, the bush II is externally eccentric with respect to the gudgeon-pin centre so that the thickness of the upper part of the bush is approximately the same as the thickness of metal of the bush beneath the grooves 2'I. The oil grooves 2l communicate through a number of holes 28 in the bush II with channels 29 in the bottom half of the bore in the top end of the connecting rod lil and these channels 29 communicate by passages 3) in the connecting rod with a central longitudinal hole 3| therein.

r he total amount of oil required for lubricating and cooling the gudgeon-pin and for cooling the piston passes up through a pipe 32 in the central 4hole 3i in the connecting rod and passes through a hole in the bush I I and through the hole 23 in the gudgeon pin into the space 2| as indicated by the arrow t1. From thence the oil passes as shown by the arrows t2 and t3 into the piston cooling space 3, which it leaves by way of the outlet passage Il as shown by the arrow t4. The oil then passes as shown by the arrow t5 into the space 25 between the gudgeon-pin I2 and the distributing member 23. The oil in the space 25 passes out through the holes 26 as shown by the arrows t6 into the oil grooves 2'| and then passes through the holes 28, channels 29 and passages 3U into and down the central hole 3| in the connecting rod,

The oil is supplied to an axial passage 34 in the crank pin 35 which has radial holes 36 leading to channels 3l in the divided bottom end bearing 38. From the channels 3l the oil passes up the central pipe 32 and from thence to the gudgeonpin and piston as already described. The oil returning down the hole 3| in the connecting rod is discharged at the lower end of the connecting rod and into the crankcase either through a pipe 39 which is open at its lower end, as shown in the left-hand half of Fig. 2, or through passages 4U and 4| in the big end bearing 38 as shown in the right-hand half of Fig. 2, the passage 4| opening below into the crankcase.

As shown in Fig. 3, the oil grooves 21 are widened at each end at 21a so that during the angular movement of the connecting rod they will always be in communication with the holes 26 in the gudgeon-pin. For the same reason the central hole 33 is elongated. The position of the channels 29 in the connecting rod top end is shown dotted in Fig. 3.

Figs. 5 and 6 show a crosshead for a singleacting internal combustion engine with gudgeonpin lubricating and provision for piston oil cooling Vsimilar to that shown in Figs. 1 to 4. The crosshead 42 has two bosses with steps 43a, 43h for the gudgeon-pin I2 and the top end of the connecting` rod IIJ is stepped and fitted with a stepped bush exactly as previously described With reference to Figs. 1-4. The top of the cross-head 42 has a flange 44 connected by bolts 45 or other fastening means to a flange 46 on the lower end of the piston rod 4l, which is provided with oil inlet and return passages IGa and I'la leading to the piston cooling space (not shown). The oil passes to the inlet passage Ia. from a central pipe in the connecting rod through the bush II, gudgeon-pin I2 and inner distributing member 20 and returns from the return passage Ila to a bore in the connecting rod through the bush, gudgeon-pin and distributing member exactly as described with reference to Figs. 1-4. The crosshead 42 has the usual shoe 48 and lubricating oil is supplied to the front and back sliding surfaces of the shoe 48 through holes 49 communieating with inner oil passages 50 supplied with oil by a passage 5| leading from the lower end of either the oil inlet passage IGa or the return passage I'Ia.

We claim:

1. In a cooling system for pistons, the combination of a piston having a cooling space and a connecting rod having two separate passages for admission and returning of cooling oil respectively, a pin connecting said piston and said connecting rod and being hollow and tted internally with an oil distributing member, said member dividing the interior of the pin into an inner and an outer space, one space being for the passage of oil from .l

the connecting rod to the cooling space of the piston and another space for the returning of the oil from the cooling space to the connecting rod.

2. A lubricating and cooling system according to claim 1, in which the pin has the shape of an open-ended tube and the oil distributing member comprises solid end discs closing the ends of said tube and united to a reduced hollow portion which separates oil ilowing to the cooling space through said hollow portion from oil iiowing around said hollow portion in returning from the piston cooling space to the connecting rod.

3. A lubricating and cooling system according to claim 1, in which the one of the two spaces in the pin is connected with the corresponding passage in the connecting rod by means of holes in the wall of the pin, said holes opening into high capacity oil grooves between the pin wall and a bearing bush of the pin, said oil grooves communicating with the said passage in the connectprovided for the pin to provide suflicient thickness for lubricating grooves in the lower part thereof. 5. ln a cooling arrangement for a piston, `a connecting rod having two separate passages for 10 Joil therein and a bearing, a hollow pin associated.

with 'said bearing and having an opening therein for communicating the interior of the pin with one of said passages, distributing-means for `conducting and directing. oil' entering the pin lthrough said opening towards a cooling space in the' piston, said distributing means having a space for receiving the cooling oil returning from the cooling space in the piston, and means associated withl the space of said distributingmeans for conducting the returning oil to the other passage of said connecting rod.

HANS HENRIK BLACHE` FREDERICK ERNESTl REBBECK; 

